Method and apparatus for converting spent water-based drilling muds into fertile indigenous top soil

ABSTRACT

A method and apparatus for converting spent water-based drilling mud into fertile indigenous top soil at a well site or location. The fertile indigenous top soil is produced by the steps of: admixing, at a well site, effective amounts of spent water-based drilling mud, mature compost, organic fertilizer, and top soil from the well site to provide a mixture containing spent water-based drilling mud, from about 30 to about 150 volume percent mature compost, from about 5 to 20 volume percent organic fertilizer, and from about 5 to 20 volume percent top soil from the well site wherein each of the volume percents is based on the volume of the spent water-based drilling mud present in the mixture; stirring the mixture for a period of time effective to form a substantially homogenous mixture; and drying the substantially homogenous mixture so as to provide fertile indigenous top soil possessing similar microbial and enzyme characteristics as the top soil at the well site.

CROSS-REFERENCE TO RELATED APPLICATIONS

This present application is a continuation of U.S. Ser. No. 11/650,906filed Jan. 8, 2007 which is a divisional of U.S. Ser. No. 10/922,254filed Aug. 19, 2004, which claims the benefit under 35 U.S.C. 119(e) ofU.S. Provisional Application Ser. No. 60/496,590, filed Aug. 20, 2003.The entire disclosures of both applications are hereby expresslyincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to treatment of spent water-based drillingmuds, and more particularly but not by way of limitation, to treatmentof spent water-based drilling muds at a drilling site to convert suchspent water-based drilling muds into indigenous fertile top soil.

BRIEF DESCRIPTION OF PRIOR ART

During the drilling of wells to recover oil and gas, it is necessary tocirculate a liquid drilling mud down the drill pipe to the bottom of thewell bore and up the well bore to the surface. The drilling mud keepsthe geologic formation surrounding the well bore in place and enhancesand maintains the ability to move the pipe up and down the well bore.Drilling muds of different weights and viscosity are required dependingupon the depth of the well, geologic formations encountered and thediameter of a well bore.

The term “drilling mud” is a term of art in the oil field industry andmay be more accurately described as a “drilling fluid”. Drilling mudscan be extremely simple or extremely complex in structure andformulation, depending on where they are used and what they are usedfor. At the simplest, drilling muds are broken into three generalcategories: 1) freshwater-based muds, 2) saltwater-based muds and 3)oil-based muds. The present invention is especially designed forconverting water-based drilling muds, both freshwater-based andsaltwater-based drilling fluids or muds, into indigenous fertile topsoil.

By definition, spent water-based drilling mud is waste. Not that it hashazardous levels of contaminates, but rather low to moderate levels ofsodium chloride. More than 98% of the total volume of spent water-baseddrilling mud are just natural ingredients, namely:

1. The liquid based water;

2. Bentonite (clay particles);

3. Barium—a weighting material; and

4. Drilling solids—earth's subsurface.

Operation of rotary drilling equipment involves rotating a drill bit bymeans of a hollow pipe. The water-based drilling mud is circulated downthe hollow pipe, through the bit and back to the surface through anannular space between the outside of the drill pipe and the inside ofthe drilled hole or casing. The water-based drilling mud performsseveral different functions in the rotary drilling operation. Examplesof some of these functions are: 1) remove formation cuttings from thedrilled hole, 2) suspend cuttings during trips, 3) form an impermeablewall cake, 4) prevent caving of the formation, and 5) control formationpressure.

A typical water-based mud system for use in the drilling of oil and gaswells includes a mud holding tank, usually positioned at the well siteon or adjacent the drilling rig, and a network of pumps, mixers and mudsupply lines that run to and from the well bore. The mud holding tank isused to hold the various dry and liquid components of the drilling mudas they are mixed into a liquid slurry to produce a drilling mud havingthe desired physical properties and characteristics.

The drilling mud is then pumped from the mud holding tank through themud supply lines and circulated through the well bore at the desiredrate. The spent drilling mud can thereafter be cleaned or reconditionedduring the drilling operation or deposited in a mud pit for subsequentremoval to a remote disposal site.

Every day, on every oil or gas drilling site, there is producedapproximately 63 gallons or one and a half barrels of spent drillingfluid per linear foot of downward drilling. Well over 90% of alldrilling mud are water-based drilling fluids, i.e. drilling muds thatuse water as the liquid base of the drilling mud, rather than oil ordiesel. Spent drilling waste requires permits in order to haul off thelocation and for disposal. The cost of analyzing, hauling and handlingof spent drilling fluid waste for disposal is very expensive. The timeframe for disposal is easy, a couple of months to a year or so forproper disposal (cradle to grave). Where the waste goes and how it ishandled is very important. The liability associated with the process ofhandling and disposing of drilling fluid waste concerns the government,the public and of course the oil companies and their waste contractors.As long as the oil and gas industry generates large amounts of spentdrilling fluid waste, the government, in response to public pressure,refuse to license oil companies to drill on public lands. If a newtechnology were developed which would provide environmental protection,new energy supplies could be found, without the negative environmentalcost. That is, if oil companies could drill for oil and gas and notgenerate any liquid or solid waste for disposal, the attitude toward oilcompanies would change overnight. The generation of waste is not theproblem, the problem is the disposal of such waste.

The present invention provides environmental technology which turnswater-based drilling waste into “fertile indigenous top soil” at thedrilling site within hours of the drilling waste being produced. The topsoil will be at least as fertile, if not more fertile, than thesurrounding soil, and will possess the same biological characteristicsas the soil at the well site. The enzymes and microorganisms in the soilpresent at the well site are already adapted to the specific climatearound the well site. Thus, no hauling, no disposal and no long termliability associated with the disposal of the spent water-based drillingfluid.

The fertile, indigenous top soil produced in accordance with the presentinvention is not just a soil conditioner or additive to topsoil, but isa complete product, in and of itself. Further, the fertile indigenoustop soil produced is site specific to each drilling location.

As will be shown hereinafter, the present invention provides a uniqueand revolutionary method of disposing of spent water-based drillingfluids. The present invention is revolutionary because millions ofbarrels of waste each year won't be hauled off location to be disposedof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial representation of an apparatus for convertingwater-based drilling muds into indigenous fertile top soil at a wellsite in accordance with the present invention.

FIG. 2 is a pictorial representation of another embodiment of anapparatus for converting spent water-based drilling muds into indigenousfertile top soil at the well site wherein the apparatus is provided withlids for closing off various compartments of the apparatus.

FIG. 3 is a side elevational view of the apparatus of FIG. 1.

FIG. 4 is a top plan view of the apparatus of FIG. 1.

FIG. 5 is a cross sectional view of the apparatus of FIG. 3 taken alongthe line 5-5 thereof.

FIG. 6 is a cross sectional view of the apparatus of FIG. 4 taken alongthe line 6-6 thereof.

DETAILED DESCRIPTION OF THE INVENTION

As previously stated, the present invention relates to a method andapparatus for converting spent water-based drilling muds into fertiletop soil at a well site or location. Broadly, the method involves thesteps of analyzing the spent water-based drilling mud to determine itspH and the presence of heavy metals, soluble salts such as sodiumchloride and hydrocarbons and petroleum products (tph). Thereafter, aplurality of dry ingredients, i.e., a humus material such as maturecompost, top soil from the well location and organic fertilizer such ascow manure, chicken manure, pig manure and the like, are admixed withthe spent water-based drilling mud to form a substantially homogeneousmixture or slurry. If the viscosity of the homogeneous mixture is toohigh due to the amount of dry ingredients mixed with the spentwater-based drilling mud or the amount of water present in the spentwater-based drilling mud, fresh water is added to the mixture until thedesired viscosity of the mixture is achieved.

The amount of the mature compost, organic fertilizer and indigenous topsoil mixed with the spent water-based drilling mud can vary. However,the mixture will generally contain an effective amount of spentwater-based drilling mud, from about 30 to 150 volume percent of maturecompost, from about 5 to 20 volume percent organic fertilizer, and fromabout 5 to 20 volume percent indigenous top soil based on the volume ofspent water-based drilling mud present in the mixture. If required, fromabout 5 to 15 volume percent of gypsum, based on the volume of spentwater-based drilling mud present in the mixture, can be incorporatedinto the mixture in order to break up or reduce the adhesivecharacteristics of the clay particles.

By incorporating an effective amount of the top soil at the welllocation with a mixture containing spent water-based drilling mud,mature compost, and the organic fertilizer, an enzyme base is providedin the mixture corresponding with the soil surrounding the well locationand the micro-organisms present in the mixture are enhanced so that thehydrocarbon present in the spent water-based drilling mud is consumed bythe enzymes while, at the same time, the nitrogen level of the resultingfertile indigenous top soil so produced is increased by the organicfertilizer.

Additional ingredients or components can be introduced into the mixture.For example, if the pH of the spent water-based drilling mud is lessthan 7, natural material, such as lime (CaO), potassium hydroxide (KOH),and the like, can be added to provide the drilling mud with a higher pHto prevent any heavy metals present in the water-based drilling mud frombecoming water soluble and to insure that heavy metals adhere to theclay particles present in the spent water-based drilling mud.

To control and/or reduce the level of water-soluble salts, such assodium chloride, an effective amount of a liquid product containingcalcium, magnesium and/or potassium and which functions as an ionexchange compound can be introduced into the mixture. The mineralspresent in the liquid product provide a mass ion effect and an ionexchange with the sodium present in the water-soluble salts.

To effect the conversion of the mixture containing the spent water-baseddrilling mud, compressed air, heated compressed air and/or 0₃ air (i.e.,pure air), can be injected into the mixture in an amount and at avelocity sufficient to substantially saturate the mixture and therebyenhances the activity of the enzymes present in the mixture, as well asto dry the resulting indigenous fertile top soil produced from themixture.

From the above, it can be appreciated that the process for convertingspent water-based drilling mud at the well site into fertile indigenoustop soil, utilizes chemical, microbial and physical principles.

Referring now to the drawings, and more particularly to FIGS. 1, 3 and 4shown therein is an apparatus 10 employed in the conversion of spentwater-based drilling muds into indigenous fertile top soil at the wellsite. The apparatus 10 includes a hopper 12 supported on a skid 14 forenhancing movement of the apparatus 10 to a desired location at the wellsite. While the apparatus 10 has been shown as having the skid 14connected to a lower portion or bottom 16 of the hopper 12, any suitablestructure can be employed in place of the skid 14, such as a pluralityof axles and wheels, as long as the structure permits the apparatus 10,and thus the hopper 12, to be easily moved to the desired location atthe well site.

The hopper 12 has a first end 17, a second end 18, a first side 20, asecond side 22 and the bottom 16. A bulk head or partition 24 is securedin the hopper 12 so as to define a first compartment 26 and a secondcompartment 28. The first compartment 26, which is adapted to receivethe spent water-based drilling mud, is provided with a mud transferassembly 30; and the second compartment 28, which is designed to receiveand treat the spent water-based drilling mud, is provided with a mixingassembly 32 for mixing the spent water-based drilling mud withadditional components such as mature compost or humus material, organicfertilizer, and indigenous soil from the well site to convert the spentwater-based drilling mud into indigenous fertile top soil utilizing theapparatus 10 and the method herein after described. In certain instance,it may be desirable to employ minor effective amounts of additives toreduce the soluble salt content and/or to increase the enzyme activityof the mixture during conversion of the mixture into indigenous fertiletop soil.

As shown in FIGS. 3-5, the apparatus 10 is further provided with adispensing assembly 34 (FIGS. 3 and 4) which is continuous with thesecond compartment 28 of the hopper 12. The dispensing assembly 34includes an auger 36 and an exit opening 38 for discharging indigenousfertile top soil produced from spent water-based drilling mud from thesecond compartment 28 of the hopper 12.

Shown in FIG. 2 is another embodiment of an apparatus 10 a constructedin accordance with the present invention. The apparatus 10 a is similarin construction to the apparatus 10 except that a first compartment 26 aof the apparatus 10 a is provided with a lid 40 and a second compartment28 a of the apparatus 10 a is provided with a lid 42. It should be notedthat the lids 40 and 42 of the apparatus 10 a are connected to a hopper12 a of the apparatus 10 a via a plurality of hinges 44 and 46,respectively, for permitting the lids 40 and 42 to be selectively movedbetween an open position and a closed position. That is, when the lid 40is in an open position spent water-based drilling mud can be introducedinto the first compartment 26 a of the apparatus 10 a; and when the lid42 of the apparatus 10 a is in an open position solid and liquidingredients can be incorporated into the second compartment 28 a formixing with the spent water-based drilling mud disposed therein. Whilethe lids 40 and 42 have been shown connected to the hopper 12 a via thehinges 44 and 46, it should be understood that the lids 40 and 42 can bedesigned for slidable engagement with the hopper 12 a or can merely besupported on the hopper 12 a so as to selectively close off the firstand second compartments 26 a and 28 a of the hopper 12 a.

Since the apparatus 10 and 10 a are similar in construction, except forthe lids 40 and 42, and their connection to the hopper 12 a via thehinges 44 and 46, only the apparatus 10 and the operation of theapparatus 10 will be described in detail hereinafter.

Referring more specifically to FIGS. 3 and 4, the first and secondcompartments 26 and 28 of the apparatus 10 will be described in moredetail, as well as the mud transfer assembly 30 for transferring thespent water-based drilling mud from the first compartment 26 of theapparatus 10 to the second compartment 28 of the apparatus 10. It shouldbe noted that while the first compartment 26 is shown as having acapacity less than about half of the capacity of the second compartment28 of the apparatus 10, the size of the first compartment 26 relative tothe second compartment 28 can be varied widely. However, when the sizeof the first compartment 26 relative to the second compartment 28 isincreased in capacity, it may be desirable to incorporate a valve (notshown) into the mud transfer assembly 30 so as to control the amount ofspent water-based drilling mud transferred from the first compartment 26of the apparatus 10 to the second compartment 28 thereof because of theamount of solid and liquid ingredients mixed with the spent water-baseddrilling mud in the second compartment 28 to produce indigenous fertiletop soil from the spent water-based drilling mud.

As previously stated, the apparatus 10 is provided with the bulk head orpartition 24 for separating the first compartment 26 of the apparatus 10from the second compartment 28 thereof. A floor 48 is provided in thefirst compartment 26 of the apparatus 10. The floor 48 is disposed adistance 50 from the bottom 16 of the hopper 12 and extends between thefirst and second sides 20 and 22 of the hopper 12, respectively, and thefirst end 17 of the hopper 12 and the bulk head or partition 24 so as toprovide a chamber 52 below the floor 48 of the first compartment 26.

As more clearly shown in FIGS. 3 and 6, the mud transfer assembly 30includes a pump 54 supported on the floor 48 of the first compartment 26and a transfer conduit 56. One end 58 of the transfer conduit 56 isconnected to the pump 54 and in fluid communication with a dischargeport 60 of the pump 54. An opposed second end 62 of the transfer conduit56 is in fluid communication with the second compartment 28 of thehopper 12 via an opening 64 formed through the bulkhead or partition 24so as to be disposed near an upper end 66 of the bulkhead or partition24 substantially as shown. The pump 54 can be any conventional pumpcapable of pumping the spent water-based drilling mud. Further, the pump54 is connected to a power source in a conventional manner. Thus, nofurther details or description of the pump 54 and its connection to apower source are believed necessary to enable a person skilled in theart to understand and practice the present invention.

The spent water-based drilling mud treated in the apparatus 10 willgenerally be filtered and/or screened prior to introduction into thefirst compartment 26 of the hopper 12 so as to remove any largeparticulate matter therefrom. However, in situations wherein the spentwater-based drilling mud is not filtered or screened, large particulatematerial may be present in the spent water-based drilling mud disposedin the first compartment 26 of the hopper 12. Thus, the pump 54 may beprovided with a cowling 68 having a plurality of openings 70 formed in alower end 72 thereof which function as filters to prevent largeparticulate matter and other large objects present in the spentwater-based drilling mud from entering an inlet port 74 of the pump 54and thereby clogging the pump 54.

Upon activation of the pump 54 spent water-based drilling fluid istransferred from the first compartment 26 of the hopper 12 into thesecond compartment 28 of the hopper 12 for admixture with compost ororganic matter, manure, indigenous soil and when required, otheradditives to lower the sodium chloride content of the spent water-baseddrilling mud or to add additional enzymes to enhance the breakdown ofhydrocarbons which may be present in the spent water-based drilling mud.Referring now to FIGS. 3-5, the mixing assembly 32, which is supportedwithin the second compartment 28 of the hopper 12, includes a shaft 78which is mounted longitudinally in the second compartment 28 of thehopper 12. The shaft 78 is mounted for rotation and is provided with aplurality of angularly disposed stirring elements or paddles 80extending radially from the shaft 78 such that upon rotation of theshaft 78, the stirring elements or paddles 80 provide substantiallyuniform movement of the mixture formed of the spent water-based drillingmud, compost or organic matter, manure, indigenous soil, ion exchangecompounds containing soil conditioners and/or gypsum, and when requiredother additives, in the second compartment 28. The angular dispositionof the stirring elements or paddles 80 will vary depending upon theoverall configuration of the second compartment 28 of the hopper 12. Theonly requirement being that the stirring elements or paddles 80 beconfigured and disposed along the shaft 78 in such a manner as toprovide the required agitation of the mixture to provide a substantiallyhomogenous mixture as a result of the substantially uniform movement ofthe mixture in the second compartment 28 of the hopper 12 duringconversion of the spent water-based drilling mud into fertile indigenoustop soil.

The shaft 78 can be driven by a motor 82 or any other drive mechanismsuch as a chain drive system and the like. Further, the motor 82 and thepump 54 can be electrically activated in a conventional manner, or themotor 82 and the pump 54 can be operated via a diesel or gasolineengine. Thus, no further comments concerning the pump 54 or the motor 82is believed necessary to anyone skilled in the art to understand andpractice the present invention.

The dispersing assembly 34 of the apparatus 10 includes the auger 36supported longitudinally in an air lock chamber 84 defined by a cylinder86 (FIG. 5) which is supported below the second compartment 28 of thehopper 12. The auger 36 is rotatably mounted in the cylinder 86 so thatupon conversion of the spent water-based drilling mud into fertileindigenous top soil and activation of a motor 82 (FIG. 3), the auger 36is rotated and fertile indigenous top soil is removed from the cylinder86 via the exit opening 38. It should be noted that the exit opening 38is provided with a cap 88 (FIGS. 2 and 3) which must be removed prior todischarging indigenous fertile top soil from the cylinder 80 and thusthe air lock chamber 84 of the dispersing assembly 34.

Referring now to FIGS. 3, 5 and 6, the apparatus 10 further includes airsupply conduits 90 and 92 for supplying compressed air, heatedcompressed air and/or 0₃ air (i.e., pure air) at high volumes, into thesecond compartment 28 of the hopper 12 to substantially saturate themixture with air and/or enhance enzyme activity on the hydrocarboncomponents present in the spent water-based drilling mud duringconversion of the spent water-based drilling mud into the desiredindigenous fertile top soil. Further, the introduction of air into thesecond compartment 28 of the hopper 12 enhances drying of the indigenousfertile top soil product produced. The air supply conduits 90 and 92extend lengthwise through the hopper 12 such that a portion of each ofthe air supply conduits 90 and 92 extending through the chamber 52 inthe first compartment 26 of the hopper 12 and a portion of the airsupply conduits 90 and 92 containing apertures 94 and 96, respectively,are disposed adjacent an opening 92 of the cylinder 80 at a position soas to not interfere with the rotational movement of the auger 36 whenthe auger 36 is activated to dispense the indigenous fertile top soilproduced in the second compartment 28 of the hopper 12 as hereinforthdescribed. Thus, air supply conduits 90 and 92 are connected to an airsupply source 98 (FIG. 1) such as a compressor, a tank or the like sothat compressed air can be injected into the second compartment 26 ofthe hopper 12 to enhance enzyme activity and thus conversion of thespent water-based drilling mud into indigenous fertile top soil inaccordance with the present invention. If required due to the ambienttemperature at the well site, the compressed air can be treated to atemperature at at least 60° F., and desirably from about 70° to 105° F.

Having described the apparatus 10 which is suitable for the conversionof spent water-based drilling mud into indigenous fertile top soil, themethod of converting such spent water-based drilling mud into indigenousfertile top soil will now be described with reference to the drawings.

To convert the spent water-based drilling mud into indigenous fertiletop soil, the apparatus 10 is moved to the well site so that the spentwater-based drilling mud can be introduced into the first compartment 26of the hopper 12. The apparatus 10 is provided with skids 14 so that theapparatus 10 can readily be moved to the well site by a vehicle. Oncethe apparatus 10 is in place, spent water-based drilling mud istransferred from the mud pit or a containment vessel into the firstcompartment 26 of the hopper 12. Desirably, the spent water-baseddrilling mud is passed through a filter and/or shaker (not shown) priorto introducing same into the first compartment 26 of the hopper 12 so asto remove any large particulate matter from the spent water-baseddrilling mud.

The spent water-based drilling mud is analyzed, either while in the mudpit or containment vessel or after it has been transferred into thefirst compartment 26 of the hopper 12 to determine the amount of solidspresent in the spent water-based drilling mud, as well as the pH of thespent water-based drilling mud, and to determine the presence of heavymetals, soluble salts, such as sodium chloride, and the totalhydrocarbon or petroleum (tph) in the spent water-based drilling mud.The analysis of the spent water based-drilling mud is important becausethe amount of solids present in the spent water-based drilling mud willdetermine the amount of the mature compost, organic fertilizer andindigenous top soil admixed with the spent water-based drilling mudand/or the necessity to add additional fresh water and the pH of thespent water-based drilling mud determines what additional components, ifany, are necessary in order to convert the spent water-based drillingmud into indigenous fertile top soil. For example, if the pH of thespent water-based drilling mud and/or the mixture resulting from mixingthe spent water-based drilling mud with compost, or organic matter,and/or organic manure (e. g., cow manure, chicken manure and hogmanure), and indigenous soil in the second compartment 28 of the hopper12 is less than 7, an effective amount of a natural material, such aslime (CaO), potassium hydroxide (KOH), and the like is incorporated intoeither the spent water-based drilling mud prior to transferring sameinto the second compartment 28, or into the mixture resulting byadmixing the spent water-based drilling mud with compost or organicmatter, manure and indigenous soil. Preferably, the pH of the spentwater-based drilling mud is determined after the spent water-baseddrilling mud has been transferred from the first compartment 26 of thehopper 12 to the second compartment 28 so that the pH of the mixtureproduced in the second compartment 28 of the hopper 12 has a pH of atleast 7, and preferably from about 7.5 to about 9.

It should be noted that by adjusting the pH to a desired range that anyheavy metals present in the spent water-based drilling mud and thus themixture in the second compartment 28 of the hopper 12, bind to clayparticles and insure that such heavy metals do not become water-soluble.

Methods of measuring the solid content of the spent water-based drillingmud and for determining the presence of heavy metals in the spentwater-based drilling mud, and/or the mixture of components including thespent water-based drilling mud in the second compartment 28 of thehopper 12 are well known. Thus no further comments or discussionconcerning the analysis of the spent water-based drilling mud and/or themixture in the second compartment 28 of the hopper 12 for presence ofheavy metals is believed necessary to enable one skilled in the art tounderstand and practice the present invention.

The spent water-based drilling mud in the mixture contained in thesecond compartment 28 of the hopper 12 is analyzed for soluble saltssuch as sodium chloride via the comprehensive salt test. As will bedescribed in more detail hereinafter, certain additives can beincorporated into the mixture contained within the second compartment 28of the hopper 12 to reduce the level of soluble salt content present infertile indigenous top soil produced in accordance with the presentinvention.

To convert the spent water-based drilling mud into indigenous fertiletop soil, effective amounts of drilling mud, mature compost, and organicmatter (e.g. animal manure such as cow manure, pig manure, chickenmanure, and the like), ion exchange compounds containing soilconditioners and/or gypsum, and indigenous soil are introduced into thesecond compartment 28 of the hopper 12. The amount of each component canvary. However, the mixture desirably contains an effective amount ofspent water-based drilling mud, from about 30 to 150 volume percentcompost, from about 5 to about 20 volume percent dry organic manure andfrom about 5 to 20 volume percent indigenous soil, based on the totalvolume of the mixture. If heavy metals are present in the spentwater-based drilling mud it may be desirable to incorporate from about 5to 15 volume percent of a material, such as gypsum, which is capable ofreducing the adhesive characteristic of the clay particles and therebyinsuring that the heavy metals remain bound to the clay and soilparticles. When it is determined that the level of soluble salts in thespent water-based drilling mud, and thus the mixture containing suchdrilling mud, is undesirable, the amount of such soluble salts can bereduced by incorporation of the aforementioned gypsum (calcium sulfate)and/or by incorporation of ion exchange compounds containing soilconditioners wherein the ion exchange compounds contain nitrogen,calcium, magnesium minerals and combinations thereof which are capableof displaying and bonding chloride ions absorbed on the surface of clayminerals colloids present in the spent water-based drilling mud. Anexample of such a commercially available ion exchange compound and soilconditioner is Nitracal-100™ and Nitracal-SC™ offered by SPL Control,L.L.C. of Elmore City, Okla.

In formulating the mixture, care should be exercised to ensure that thecompost is mature compost to prevent an endothermic reaction which wouldheat the fertile indigenous top soil produced to a temperature beyondhealthy temperature for plant growth and seed germination.

The addition of dry organic manure not only increases the presence ofnitrogen in the fertile indigenous top solid produced in accordance withthe present invention, but also introduces new microbes and enzymes intothe resulting soil product. The incorporation of the indigenous top soilprovides the soil produced from the spent water-based drilling mud withthe same microorganisms and enzymes as the soil surrounding the wellsite. The mature compost function as organic food for the microorganismsand the nitrogen from the dry organic manure speeds up themultiplication or growth of the microorganisms or microbes which arepresent in spent water-based drilling mud. In the event the mixturebecomes to viscose, fresh water may be added to the mixture to enhancemixing.

In most instances, the microorganisms and enzymes present in theindigenous top soil are sufficient to degrade or metabolize anyhydrocarbon or petroleum products present in the spent water-baseddrilling mud. However, if it is determined that additional enzymesshould be added, various types of enzymes and/or micro-organisms capableof degrading the hydrocarbon and petroleum products which are well knownin the art can be employed.

The mixture present in the second compartment 28 of the hopper 12 isthoroughly mixed via the stirring elements or paddles 80 so thatsubstantially uniform movement of the mixture is provided throughout thesecond compartment 28 of the hopper 12 whereby a substantiallyhomogenous mixture or slurry is formed. Thereafter, in order to furtheractivate the enzymes, compressed air, heated compressed air or 0₃ (i.e.pure air), may be injected into the mixture via the apertures 94 and 96of the air supply conduits 90 and 92, respectively. The air is desirablymaintained at a temperature of at least 60° F., and preferably fromabout 70° F. to about 105° F. However, care should be exercised toensure that the temperature of the air is not sufficient to heat themixture contained in the second compartment 28 of the hopper 12 to atemperature sufficient to kill or destroy any enzyme activity of themixture.

Depending on the solid or clay content of the spent water-based drillingmud, it may be desirable to incorporate into the mixture an effectiveamount of gypsum, i.e., and/or ion exchange compounds containing soilconditioners from. The effective amount of gypsum and/or ion exchangecompounds containing soil conditioners can vary widely depending uponthe composition of the spent water-based drilling mud. However, theamount of gypsum and/or ion exchange compounds containing soilconditioners will generally be present in an amount of about 5 to 15percent by volume, based on the volume of the spent water-based drillingmud. The gypsum reduces the adhesive properties of the clay therebyincreasing the distance between the clay particles so that chloride ionscan be removed by the ion exchange compounds. Further, the sodium canmigrate throughout the fertile indigenous top soil produced inaccordance with the present invention and thus, prevent destruction orburning of the roots and seeds of plants planted in such soil.

Once it is determined that the spent water-based drilling mud has beenconverted into indigenous fertile top soil, the air can be continued tobe supplied into the second compartment 28 of the hopper 12 until thefertile indigenous top soil is in a semi-dried state. Thereafter, theflow of air is ceased, and the cap 88 is removed so that the exitopening 38 of the cylinder 86 is in an open condition. The auger 36 isthen activated and the semi-dried fertile indigenous top soil producedfrom the spent water-based drilling mud is removed from the secondcompartment 28 of the hopper 12 and analyzed to determine the saltprofile of such soil. The dried, fertile indigenous top soil so producedcan be used in agricultural purposes at the location of the well or atother sites.

In order to further explain the present invention, the following exampleis set forth. However, it is to be understood that the example is forillustrative purposes and are not intended to limit the scope of thepresent invention.

EXAMPLE

Spent water-based drilling mud was collected from three different welllocations in the Anadarko basin. These wells represent the truecharacter of the contaminate profile of water-based drilling mud used atthose three specific well locations. The waste drilling mud from eachlocation was mixed to form a fertile indigenous top soil containing 70volume percent commercial compost, 20 volume percent cow manure, 5volume percent sand, 10 volume percent gypsum, and 20 volume percentindigenous top soil to form a substantially uniform mixture. The soilwas then taken to Oklahoma State University at Oklahoma City, Okla.Seeds of native grasses and small plants were germinated and grown inthe samples of the indigenous top soil produced from the water-baseddrilling mud. The seeds of the native grasses and small plants wereplanted in the indigenous top soil produced using the spent water-baseddrilling muds are growing and the tomato plants are producing beautifuland delicious tomatoes. It should be noted that there wasn't anythingthat was taken out of the drilling mud waste to make the fertileindigenous top soil, it was added. This example clearly shows that theliquid and solid waste from drilling oil and gas wells does not have toleave the location but can be turned into fertile indigenous top soilwithin a few hours and used to grow any native commercial crop orvegetation. The top soil is complete in and of itself; not just a soiladditive or conditioner. Thus, the soil can start, sustain and bearbeautiful edible fruit. Each well sites top soil has the samemicroorganisms and enzymes as in the surrounding soil where the well wasdrilled. Further, the top soil made from the spent water-based drillingmuds will have both mineral and organic fertility, greater enzymeactivity surrounded by organic food and genetically the samemicroorganisms and enzymes as the surrounding soil at each well site,thereby resulting in more fertile indigenous top soil, capable ofgrowing a better grade of vegetation than around the well site.

It should be understood that the method and apparatus employed in theconversion of spent water-based drilling mud into fertile indigenous topsoil can incorporate additional steps, features or even ingredients forimproving the overall composition and properties of the fertileindigenous top soil produced from the spent water-based drilling mud. Inaddition, it should be noted that changes may be made in theconstruction and operation of the apparatus, elements, assemblies and inthe step or steps or sequence of steps of the methods described hereinwithout departing from the spirit and scope of the invention as definedin the following claims.

1. A method for producing fertile indigenous top soil at a well siteemploying spent water-based drilling mud recovered at the well sitewherein the fertile indigenous top soil possesses similar microbial andenzyme characteristics as soil at the well site, the fertile indigenoustop soil produced by a method comprising the steps of: providing anapparatus having a hopper, the hopper provided with at least onecompartment having a mixing assembly and at least one air supply conduitfor supplying air into the at least one compartment; moving theapparatus to a position near the well site; admixing effective amountsof spent water-based drilling mud, mature compost, organic fertilizer,and top soil in the at least one compartment of the hopper to provide amixture containing spent water-based drilling mud, from about 30 toabout 150 volume percent mature compost, from about 5 to 20 volumepercent organic fertilizer, and from about 5 to 20 volume percent topsoil from the well site wherein each of the volume percents is based onthe volume of the spent water-based drilling mud present in the mixture;activating the mixing assembly so as to stir the mixture for a period oftime effective to form a substantially homogenous mixture; drying thesubstantially homogenous mixture so as to produce fertile indigenous topsoil possessing similar microbial and enzyme characteristics as the topsoil surrounding the well site; and removing the fertile indigenous topsoil from the at least one compartment of the hopper.
 2. The method ofclaim 1 wherein, in the step of providing the apparatus, the at leastone compartment of the hopper is provided with a discharge assembly forremoving the fertile indigenous top soil from the at least one firstcompartment.
 3. The method of claim 2 wherein the mixture formed in theat least one compartment is maintained at a pH in a range of from about7 to about 9.5.
 4. The method of claim 3 further comprises admixing fromabout 5 to about 15 volume percent gypsum, based on the volume of spentwater-based drilling mud present, into the mixture so as to break up andreduce adhesive characteristics of clay particles present in the spentwater-based drilling mud.
 5. The method of claim 1 wherein the methodfurther comprises admixing from about 5 to about 15 volume percentgypsum, based on the volume of spent water-based drilling mud, into themixture so as to break up and reduce adhesive characteristics of clayparticles present in the spent water-based drilling mud.
 6. The methodof claim 1 wherein the mixture is maintained at a pH in a range of fromabout 7 to about 9.5.
 7. The method of claim 6 wherein the methodfurther comprises injecting an effective amount of air into the mixtureto enhance enzyme and microbial activity on hydrocarbons componentspresent in the spent water-based drilling mud.
 8. The method of claim 7wherein the air is injected into the mixture in an amount and at avelocity sufficient to dry the mixture and thereby provide the fertileindigenous top soil.
 9. The method of claim 8 wherein the temperature ofthe air is at least 60° F.
 10. The method of claim 9 wherein thetemperature of the air supply is from about 70 to about 105° F.
 11. Themethod of claim 1 wherein the method further comprises injecting aneffective amount of air into the mixture to enhance enzyme and microbialactivity on hydrocarbons components present in the spent water-baseddrilling mud.
 12. The method of claim 11 wherein the air is injectedinto the mixture in an amount and at a velocity sufficient to dry themixture and thereby as provide the fertile indigenous top soil.
 13. Themethod of claim 12 wherein the temperature of the air supply is at least60° F.
 14. The method of claim 13 wherein the temperature of the airsupply is from about 70 to about 105° F.
 15. The method of claim 14wherein the method further comprises admixing from about 5 to about 15volume percent gypsum, based on the volume spent water-based drillingmud, into the mixture so as to break up and reduce adhesivecharacteristics of clay particles present in the spent water-baseddrilling mud.
 16. The method of claim 15 wherein the mixture ismaintained at a pH in a range of from about 7 to about 9.5.